Intermittent Hard Starting

[RonnieH]

I'm still troubleshooting a hard starting problem when the car sits in the sunlight. I checked several places, but can anyone confirm if there is indeed a check-valve in the fuel system ('90 Coupe). If so, where is it located. I would assume it is part of the fuel pump assembly, but in looking at a schematic, it doesn't show a check valve. Before I pull the fuel pump (if there is a check valve there), I am going to do one other simple step - replace the fuel tank cap. I noticed awhile back there were gas fumes at he back of the car when I walked by it. When I remove the cap, I don't hear any pressure being relieved. I looked at the rubber "O" ring. It looks o.k., but that doesn't really mean anything.

Thanks for any help.

 

[lex luther]

I can not tell what you are meaning by "hard start". My wife's 90 has refused to start (no start) on hot days when she pulls into the parking lot for a quick stop and then trys to restart, without any success. After about 30 minutes or so, it will start without any problem. While it was immediately thought to be the VATS, it did not seem to happen in colder weather. Also, after the last starter replacement, the problem has not resurfaced (but I suspect it will happen again given enough time), and I assume it is related to "hot starter."

 

[Robertwav1]

I'm still troubleshooting a hard starting problem when the car sits in the sunlight. I checked several places, but can anyone confirm if there is indeed a check-valve in the fuel system ('90 Coupe). If so, where is it located. I would assume it is part of the fuel pump assembly, but in looking at a schematic, it doesn't show a check valve. Before I pull the fuel pump (if there is a check valve there), I am going to do one other simple step - replace the fuel tank cap. I noticed awhile back there were gas fumes at he back of the car when I walked by it. When I remove the cap, I don't hear any pressure being relieved. I looked at the rubber "O" ring. It looks o.k., but that doesn't really mean anything.

Thanks for any help.

Well, you're assuming fuel pressure is not there when this is happening. Okay, if that's the case, check the regulator. Sunlight or heat can affect the way it operates. There is a check in the fuel pump. It's a mechanical reed type which rarely goes bad. I would think the pump would wear out before that. The fact that you smell fuel tells you there is a leak. If it gets sucked up in the vacuum portion of the engine it can be very misleading. Just a thought...look at the reg.

 

[Chetzki]

My truck has been doing the same thing for months where it would start right up when it was cold or just shut off and restarted. It was worse when it sat out in the sun on a warm/hot day. I never smelled gas though.

All my troubleshooting and asking on the Chevy truck forum led me to believe it was the fuel pressure regulator or fuel pump. I started taking the manifold off to get to the regulator and discovered a fuel line fitting that I could loosen with my fingers. Tightened that up and now it fires up in fractions of a second.

Check all your fuel line fittings. I would have never found this one if I hadn't started taking stuff off.

Chetzki